Tissue fibrinolysis in experimental gastric ulcer: a study in the rat.

Gastric mucosal lesions were induced in rats by pyloric ligature and intragastric instillation of hydrochloric acid. Within 4 h all rats developed focal mucosal lesions. Early regeneration was observed 72 h after release of the pyloric ligature and replacement of the hydrochloric acid by a phosphate buffer. A significantly increased gastric mucosal fibrinolytic activity was found 4 h after pylorus ligation. The submucosal vascular fibrinolysis remained unchanged. Following release of the pyloric ligature the increased mucosal fibrinolysis returned to normal values after 72 h. Intravenous administration of tranexamic acid significantly decreased the mucosal and vascular fibrinolytic activity without influencing the formation of induced gastric lesions. Increased mucosal fibrinolysis is probably not involved in the development of mucosal lesions.